The Senate will be a very different place after the arrival of two new Democratic senators: Doug Jones, the winner of Tuesday’s stunning upset in Alabama, and Tina Smith, who was tapped on Wednesday to fill the pending vacancy in Minnesota. (CQ Roll Call file photos)

Turns out, the Senate is going to be quite a different place next year even without Roy Moore — and that’s not only because senators named Smith and Jones will be serving together for the first time in 86 years.

The chamber will have its closest partisan split in a decade, and the narrowest divide in favor of the Republicans since the spring of 2001. The roster of women will expand to a record 22, and for the first time a pair of women will comprise the Senate delegations of four states. The Deep South will be represented by a Democrat for the first time in four years.

And those are only the most prominent quantifiable changes being wrought by the arrival of two new Democratic senators: Doug Jones, the winner of Tuesday’s stunning upset in Alabama, and Tina Smith, who was tapped on Wednesday to fill the pending vacancy in Minnesota.

They will spawn a fresh set of tactical shifts and some political repositioning by both parties in 2018. Subtle changes to the legislative agenda for the midterm election year are also in the offing.

Watch: Scenes From Doug Jones' Election Night Rally

In a club with only a hundred members and where seniority is of abiding importance, the arrival of even two newcomers will alter the rhythms of the place.

Both are expected to take office early in January. Jones, a prominent lawyer who was Alabama’s top federal prosecutor in the late 1990s, will do so assuming his narrow victory is certified after the state’s three-week timetable. Smith, Minnesota’s lieutenant governor since 2015, will do so assuming fellow Democrat Al Franken, who promised last week to resign in the face of an array of sexual harassment allegations, decides not to return in the new year.

Now that Republicans have cut their deal on a tax package, sounding confident of pushing it through the House and Senate next week, Jones and Smith will not be called on to join their party’s united effort to block the cuts for businesses and wealthy people. But they’ll still be part of a headline-making fiscal policy debate within weeks of taking office, when the climactic if overdue decisions about fiscal 2018 spending are likeliest to get made.

Showdowns over raising the debt limit, preventing deportation of undocumented immigrants who arrived as children, confirming judicial nominees, setting new limits on the use of military force and updating agriculture polices (an important parochial concern in both Alabama and Minnesota) are all likely early in the new arrivals’ tenure.

Finding a spot

As newcomers to federal office, both have some leeway to position themselves on the congressional Democratic spectrum. But both will be pressed to stake their spots quickly, so Minority Leader Charles E. Schumer can know when he can count on them in the polarized partisan battles certain to keep defining Senate legislative life.

Whenever the Democratic Caucus — expanded to 49 members once Jones is sworn in — presents a united front, Majority Leader Mitch McConnell will have just one vote to spare when trying to confirm a nomination (which can no longer be filibustered) along party lines. This means such centrists as Susan Collins of Maine, and such iconoclasts as Bob Corker of Tennessee, will have even more leverage than they do now. And when he tries to advance the GOP legislative agenda over the 60-vote cloture threshold, McConnell will need to find at least nine cooperative Democrats from now on.

All told, it’s the toughest hand dealt a Republican majority leader since the early days of George W. Bush’s presidency. Then there were 50 GOP senators plus Vice President Dick Cheney to break a tie, although in June of 2001 the majority flipped to the Democrats thanks to a party switch by Vermont’s Jim Jeffords.

The slimmed margin will also influence the work of committees. Since the GOP holds a one-chair advantage on every panel except Finance and Judiciary (where they have a two-seat edge), panels may need to add members on both sides, or a few senators will need to give up an assignment, if Jones and Smith are to get a full complement of assignments.

The long game

Of the two, Jones remains by far the bigger ideological mystery, although his platform deviated little from that of the national party. The policymaking personality he cultivates will help define how Democrats present for the coming campaign — more as the party of resistance to President Donald Trump or as the party with a centrist-sounding, proactive plan for taming economic anxieties.

The extent of the party’s midterm gains will also help shape the long-term prospects for Jones, who’s guaranteed just three years in office after becoming the first Democratic winner of an Alabama Senate seat in a quarter-century. Trump carried the state by 28 points last year, and Jones’ improbable triumph came despite losing six of the seven congressional districts — reminders his state is an anchor of a region that’s still deeply red and his election was mainly a referendum on Republican Moore and his alleged child molesting.

(Both the Deep South’s two most recent Democratic senators, Mary Landrieu of Louisiana and Mark Pryor of Arkansas, were defeated in 2014.)

In contrast, Smith seems certain to align unambiguously in the center-left mainstream of the caucus. That notion was buttressed when Rep. Keith Ellison of Minneapolis, a prominent backer of Vermont Sen. Bernie Sanders’ presidential campaign, put his own Senate ambitions on hold Wednesday by labeling Smith “a progressive champion” and endorsing her in the November special election for the final two years of Franken’s term.

Smith will begin the year as the solid but not prohibitive favorite in a state where Democrats have dominated major races even though Trump came within 2 points if winning. (Her new Senate colleague, Amy Klobuchar, looks to be a safe bet for a third term.)

Both new senators got their start in politics as staffers to elected officials. Jones, now 63, secured his first job out of law school as a Senate Judiciary Committee counsel for Howell Heflin, the Alabama Democrat whose old seat Jones will soon be occupying. Smith, 59, ran a marketing firm before signing on as chief of staff to Minneapolis Mayor R.T. Rybak and then Mark Dayton after he won the governorship in his political comeback after a single term in the Senate.

The two also share two of the four most common surnames in the nation, but those haven’t appeared together on a Senate roster since 1932. That fall, onetime GOP Whip Wesley Jones of Washington was swept out in the Roosevelt landslide, leaving behind Democrat “Cotton Ed” Smith of South Carolina.